Method of manufacturing heat sink plate

ABSTRACT

A heat sink manufacturing method includes the steps of positioning a heat conductive sheet on a lower half holding tool of a powder feeder; tightly closing and connecting an upper half holding tool of the power feeder to the lower half holding tool, such that spacers downward extended from the upper half holding tool are in tight contact with the heat conductive sheet; dispensing metal powder on the heat conductive sheet via a powder inlet on the upper half holding tool and under a positive pressure while vibrating the heat conducting sheet for the metal powder to uniformly distribute on the heat conductive sheet; opening the upper half holding tool and spraying an organic liquid on the metal powder for the same to set; and removing the heat conductive sheet from the lower half holding tool and sintering the metal powder to the heat conductive sheet.

FIELD OF THE INVENTION

The present invention relates to a method of manufacturing heat sink plate, and more particularly to a heat sink plate manufacturing method that requires only reduced tool and assembling costs while enables copper powder to uniformly distribute on and be sintered to the heat sink plate.

BACKGROUND OF THE INVENTION

With the progress in the scientific and technological fields, the currently available electronic devices have higher and higher operating performance and also produce more heat during the operation thereof. Therefore, the demand for heat sinks with increased heat dissipation efficiency also increases. To enable increased heat dissipation efficiency, most of the conventional heat sinks include a plurality of stacked radiating fin assemblies. Therefore, a lot of manufacturers have engaged in the research and development in radiating fins, and high-efficiency heat sinks have become the most important target in the industrial field now.

Taking a computer as an example, the central processing unit (CPU) thereof produces the largest part of heat in the computer. The CPU will have reduced performance when the heat produced by it constantly increases. When the heat accumulated in the CPU exceeds a high limit, it will result in shutdown or other serious damages of the computer. Moreover, to solve the problem of electromagnetic wave radiation, all important components and parts of the computer are enclosed in a computer case. Therefore, it is a very important issue to quickly remove the heat produced by the CPU and other electronic elements of the computer from the computer case.

Currently, a heat sink plate is frequently used with processors, chips and illuminating devices for dissipating the heat produced during the operation of these items. The heat sink plate has high thermal conductivity, quick heat transfer and large contact area with heat-producing elements, and does not consume electric power, and is therefore very suitable for use with heat-producing elements to transfer and dissipate the heat produced by the heat-producing elements.

According to the currently available heat sink plate, it mainly includes two copper sheets connected to each other. Between the two copper sheets, copper powder is distributed and a plurality of spacers is provided. The spacers are firmly arranged between and connected to the two copper sheets, and the copper powder is uniformly located around the spacers. In brief, the conventional heat sink plate involves complicated manufacturing procedures to complete it.

FIG. 1 is a flowchart showing the steps included in a conventional heat sink plate manufacturing method. The steps include:

associating a central mould with a copper sheet (step S11); filling metal powder between the central mould and the copper sheet (step S12); vibrating the copper sheet and the central mould (step S13); sintering the central mould and the copper sheet that have the metal powder filled therebetween (step S14); and removing the central mould from the copper sheet after the sintering (step S15).

According to the above-described conventional technique for manufacturing the heat sink plate, the central mould is associated with the copper sheet that serve as an upper or a lower metal cover. Then, the metal powder is filled between the central mould and the copper sheet, and the copper sheet and the central mould are vibrated to uniformly distribute the metal powder therebetween. Thereafter, the central mould and the copper sheet along with the uniformly distributed metal powder are positioned in a sintering furnace and sintered at high temperature. After the high-temperature sintering, the metal powder forms a layer of capillary structure on an inner surface of the copper sheet. Finally, the central mould is removed from the copper sheet. In the sintering furnace, there is a plurality of copper sheets positioned in the sintering furnace at the same time for sintering, and each of the copper sheets has one central mould associated therewith. Therefore, a plurality of central moulds is needed to enable sintering a plurality of copper sheets and metal powder at the same time. As a result, high costs are required to prepare a large number of central moulds and filling the metal powder. Moreover, since it is necessary to form a plurality of recesses on the sintered copper sheet at the sintered metal powder, a plurality of extended posts must be provided on the central mould for forming such recesses. Before the sintering is completed, the central mould must not be removed from the copper sheet, lest the metal powder should shift to and thereby eliminate the spaces in the recesses due to any movement of the copper sheet. This also necessitates the copper sheet to be sintered along with the central mould.

In brief, the conventional heat sink plate manufacturing method has the following disadvantages: (1) requiring high mould cost; (2) involving troublesome manufacturing procedures; and (3) increasing the overall manufacturing cost of the heat sink plate.

It is therefore tried by the inventor to develop an improved heat sink plate manufacturing method to overcome the problems in the prior art.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide a heat sink plate manufacturing method that enables reduced tools and accordingly, reduced tool cost.

Another object of the present invention is to provide a heat sink plate manufacturing method that has simplified procedures to save the manufacturing and assembling costs.

A further object of the present invention is to provide a heat sink plate manufacturing method that effectively enables uniform distribution of metal powder on the heat sink plate.

A still further object of the present invention is to provide a heat sink plate manufacturing method that is able to effectively prevent the heat conductive sheets for forming the heat sink plate from moving during the manufacturing process, and accordingly, prevents the metal powder from shifting before being sintered to the heat conductive sheets.

A still further object of the present invention is to provide a heat sink plate manufacturing method that ensures good levelness of the manufactured heat sink plate.

To achieve the above and other objects, the heat sink plate manufacturing method of the present invention includes the steps of positioning a heat conductive sheet on a lower half holding tool of a powder feeder; tightly closing and connecting an upper half holding tool of the power feeder to the lower half holding tool, such that spacers downward extended from the upper half holding tool are in tight contact with the heat conductive sheet; dispensing metal powder on the heat conductive sheet via a powder inlet on the upper half holding tool while vibrating the heat conducting sheet for the metal powder to uniformly distribute on the heat conductive sheet; opening the upper half holding tool and spraying an organic liquid on the metal powder for the same to set on the heat conductive sheet; and removing the heat conductive sheet from the lower half holding tool and sintering the metal powder to the heat conductive sheet.

With the heat sink plate manufacturing method of the present invention, only reduced tool and assembling costs are required; the metal powder can be uniformly distributed on the heat conductive sheets; and the problem of shifting metal powder in the process of manufacturing due to moved heat conductive sheets can be effectively prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein

FIG. 1 is a flowchart showing the steps included in a conventional method of manufacturing a heat sink plate;

FIG. 2 is a flowchart showing the steps included in a method of manufacturing heat sink plate according to a first preferred embodiment of the present invention;

FIG. 3 is a flowchart showing the steps included in a method of manufacturing heat sink plate according to a second preferred embodiment of the present invention; and

FIGS. 4 to 9 are schematic views illustrating the manufacturing of a heat sink plate using the method of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please refer to FIG. 2 that is a flowchart showing the steps included in a method of manufacturing heat sink plate according to a first preferred embodiment of the present invention, and to FIGS. 4, 5, 6 and 8 that illustrate the manufacturing of a heat sink plate using the method shown in FIG. 2.

As shown in FIG. 2, the method of manufacturing heat sink plate according to the first preferred embodiment of the present invention includes the steps of:

positioning a heat conductive sheet 2 on a lower half holding tool 11 of a powder feeder 1 (step S21); tightly closing and connecting an upper half holding tool 12 of the power feeder 1 to the lower half holding tool 11 (step S22); dispensing metal powder 3 on the heat conductive sheet 2 while vibrating the heat conducting sheet 2, so that the metal powder 3 is uniformly distributed on the heat conductive sheet 2 (step S23); opening the upper half holding tool 12 and spraying an organic liquid 4 on the metal powder 3 that has been uniformly distributed on the heat conductive sheet 2 (step S24); and removing the heat conductive sheet 2 from the lower half holding tool 11 and sintering the metal powder 3 to the heat conductive sheet 2 (step S25).

In the illustrated first embodiment, the heat conductive sheet 2 is a copper sheet. As can be seen from FIG. 4, the copper heat conductive sheet 2 is positioned on the lower half holding tool 11 of the powder feeder 1, and the lower half holding tool 11 is provided on a top with a receiving space being configured to the shape of the heat conductive sheet 2, so that the heat conductive sheet 2 is fixedly set in the receiving space of the lower half holding tool 11. Then, the upper half holding tool 12 of the powder feeder 2 is tightly closed and connected to the lower half holding tool 11, as shown in FIGS. 5 and 6. As can be seen from FIG. 4, the upper half holding tool 12 is provided on a lower side facing toward the lower half holding tool 11 with a plurality of spacers 121, which are in tight contact with the heat conductive sheet 2 when the upper half holding tool 12 is closed onto the lower half holding tool 11. After the upper half holding tool 12 has been closed and connected to the lower half holding tool 11, metal powder 3, such as copper powder or aluminum powder, is fed onto the heat conductive sheet 2 via a powder inlet 122 formed on the upper half holding tool 12. Meanwhile, the powder feeder 1 drives the lower half holding tool 11 to vibrate while feeding the metal powder 3, so that the metal powder 3 is uniformly distributed on the heat conductive sheet 2. The metal powder 3 uniformly distributed on the heat conductive sheet 2 is divided by the spacers 121 into several areas. When the upper half holding tool 12 is removed to open the lower half holding tool 11, the spacers 121 extended from the lower side of the upper half holding tool 12 are separated from the heat conductive sheet 2 at the same time, leaving a plurality of recesses 31 on the uniformly distribute metal powder 3 at positions corresponding to the spacers 121, as shown in FIG. 8. Then, the organic liquid 4, such as alcohol or acetone, is sprayed onto the metal powder 3 on the heat conductive sheet 2 to set the metal powder 3 and maintain the recesses 31 in shape. Thereafter, the heat conductive sheet 2 can be separated from the lower half holding tool 11 for use in subsequent process. Two heat conductive sheets 2 both having the metal powder 3 set thereon in the above manner are then assembled to each other and moved to a graphite plate (not shown) to sinter the metal powder 3 to the heat conductive sheets 2 and complete the manufacture of a heat sink plate.

With the heat sink manufacturing method according to the first preferred embodiment of the present invention, the heat sink plate can be manufactured with reduced tools and simplified procedures. The method of the present invention can effectively overcome the problems of shifting metal powder when the heat conductive sheets are moved in the process of manufacturing. Moreover, as shown in FIG. 9, a plurality of supporting elements 32 can be separately positioned in the recesses 31 on the set metal powder 3 before two pieces of the heat conductive sheets 2 are assembled to each other. With the two heat conductive sheets 2 being internally supported by the supporting elements 32, the heat conductive sheets 2 undergone sintering can have good levelness.

Please refer to FIG. 3 that is a flowchart showing the steps included in a method of manufacturing heat sink plate according to a second preferred embodiment of the present invention. The method in the second preferred embodiment is different from that in the first preferred embodiment in some of the steps. As shown, the heat sink plate manufacturing method in the second preferred embodiment includes the steps of:

Moving a lower half holding tool 11 of a powder feeder 1 to an outer side of the powder feeder 1 via a sliding mechanism 13 thereof (step S31); positioning a heat conductive sheet 2 on the outward moved lower half holding tool 11 of the powder feeder 1 (step S32); tightly closing and connecting an upper half holding tool 12 of the power feeder 1 to the lower half holding tool 11, and using the sliding mechanism 13 to move the closed lower and upper half holding tools 11, 12 back into the powder feeder 1 (step S33); dispensing metal powder 3 on the heat conductive sheet 2 while vibrating the heat conducting sheet 2, so that the metal powder 3 is uniformly distributed on the heat conductive sheet 2 under a positive pressure (step S34); moving the closed lower and upper half holding tools 11, 12 out of the powder feeder 1 via the sliding mechanism 13, and opening the upper half holding tool 12 and spraying an organic liquid 4 on the metal powder 3 that has been uniformly distributed on the heat conductive sheet 2 (step S35); and removing the heat conductive sheet 2 from the lower half holding tool 11 and sintering the metal powder 3 to the heat conductive sheet 2 (step S36).

As can be best seen from FIGS. 4 to 7, in the illustrated second embodiment, the powder feeder 1 is provided below the lower half holding tool 11 with a sliding mechanism 13, such that the lower half holding tool 11 can be sidewardly moved out of the powder feeder 1 via the sliding mechanism 13. The heat conductive sheet 2 is also a copper sheet in the second embodiment. As can be seen from FIG. 4, the copper heat conductive sheet 2 is positioned on the lower half holding tool 11 of the powder feeder 1, and the lower half holding tool 11 is provided on a top with a receiving space being configured to the shape of the heat conductive sheet 2, so that the heat conductive sheet 2 is fixedly set in the receiving space of the lower half holding tool 11. Then, the upper half holding tool 12 of the powder feeder 2 is tightly closed and connected to the lower half holding tool 11, and the closed lower and upper half holding tools 11, 12 are moved back into the powder feeder 1 via the sliding mechanism 13, as shown in FIGS. 5 and 6. As can be seen from FIG. 4, the upper half holding tool 12 is provided on a lower side facing toward the lower half holding tool 11 with a plurality of spacers 121, which are in tight contact with the heat conductive sheet 2 when the upper half holding tool 12 is closed onto the lower half holding tool 11. After the closed lower and upper half holding tools 11,12 have been moved back into the powder feeder 1 via the sliding mechanism 13, metal powder 3, such as copper powder or aluminum powder, is fed onto the heat conductive sheet 2 via a powder inlet 122 formed on the upper half holding tool 12. As can be seen from FIG. 7, in the second embodiment, a pressure-supply device 14 is connected to a vessel of the powder feeder 1 having the metal powder 3 contained therein. To dispense the metal powder 3 over the heat conductive sheet 2, the pressure-supply device 14 is caused to generate an amount of positive-pressure airflow for forcing the metal powder 3 forward, so that the metal powder is dispensed on the heat conductive sheet 2 under a positive pressure. Meanwhile, the powder feeder 1 drives the lower half holding tool 11 to vibrate while feeding the metal powder 3, so that the metal powder 3 is uniformly distributed on the heat conductive sheet 2. The duration of vibrating the lower half holding tool 11 can be set on the powder feeder 1. The metal powder 3 uniformly distributed on the heat conductive sheet 2 is divided by the spacers 121 into several areas. When the upper half holding tool 12 is removed to open the lower half holding tool 11, the spacers 121 extended from the lower side of the upper half holding tool 12 are separated from the heat conductive sheet 2 at the same time, leaving a plurality of recesses 31 on the uniformly distribute metal powder 3 at positions corresponding to the spacers 121, as shown in FIG. 8. Then, the organic liquid 4, such as alcohol or acetone, is sprayed onto the metal powder 3 on the heat conductive sheet 2 to set the metal powder 3 and maintain the recesses 31 in shape. Thereafter, the heat conductive sheet 2 can be separated from the lower half holding tool 11 for use in subsequent process. Two heat conductive sheets 2 both having the metal powder 3 set thereon in the above manner are then assembled to each other and moved to a graphite plate (not shown) to sinter the metal powder 3 to the heat conductive sheets 2 and complete the manufacture of a heat sink plate.

With the heat sink manufacturing method according to the second preferred embodiment of the present invention, the heat sink plate can be manufactured with reduced tools and simplified procedures. The method of the present invention can uniformly distribute the metal powder 3 on the heat conductive sheet 2 and effectively overcome the problem of shifting metal powder when the heat conductive sheet is moved in the process of manufacturing. Moreover, as shown in FIG. 9, a plurality of supporting elements 32 can be separately positioned in the recesses 31 on the set metal powder 3 before two pieces of the heat conductive sheets 2 are assembled to each other. With the two heat conductive sheets 2 being internally supported by the supporting elements 32, the heat conductive sheets 2 undergone the sintering can have good levelness.

According to the above description, it can be found the heat sink manufacturing method according to the present invention has the following advantages: (1) requiring only reduced tools; (2) requiring reduced assembling cost; (3) enabling uniform distribution of the metal powder on the heat conductive sheets; (4) effectively preventing the metal powder from shifting in the process of manufacturing; and (5) enabling the heat conductive sheets undergone sintering to have good levelness. 

1. A method of manufacturing heat sink plate, comprising the steps of: positioning a heat conductive sheet on a lower half holding tool of a powder feeder; tightly closing and connecting an upper half holding tool of the power feeder to the lower half holding tool; dispensing metal powder on the heat conductive sheet while vibrating the heat conducting sheet, so that the metal powder is uniformly distributed on the heat conductive sheet; and opening the upper half holding tool and removing the heat conductive sheet from the lower half holding tool, and sintering the metal powder to the heat conductive sheet.
 2. The method of manufacturing heat sink plate as claimed in claim 1, wherein the metal powder is dispensed on the heat conductive sheet under a positive pressure.
 3. The method of manufacturing heat sink plate as claimed in claim 1, wherein the upper half holding tool is provided with a powder inlet, and the metal powder is dispensed onto the heat conductive sheet via the powder inlet.
 4. The method of manufacturing heat sink plate as claimed in claim 1, further comprising a step of spraying an organic liquid on the metal powder uniformly distributed on the heat conductive sheet before the heat conductive sheet is removed from the lower half holding tool for sintering.
 5. The method of manufacturing heat sink plate as claimed in claim 4, wherein the organic liquid is a metal-powder-affinity liquid enabling the metal powder having the organic liquid sprayed thereon to set on the heat conductive sheet.
 6. The method of manufacturing heat sink plate as claimed in claim 5, wherein the organic liquid is selected from the group consisting of alcohol and acetone.
 7. The method of manufacturing heat sink plate as claimed in claim 1, wherein the upper half holding tool is provided on a lower side with a plurality of spacers, the spacers being in tight contact with the heat conductive sheet when the upper half holding tool is closed onto the lower half holding tool, such that a plurality of recesses are formed on the heat conductive sheet when the metal powder is distributed on the heat conductive sheet.
 8. The method of manufacturing heat sink plate as claimed in claim 1, wherein the metal powder is selected from the group consisting of copper powder and aluminum powder.
 9. The method of manufacturing heat sink plate as claimed in claim 1, further comprising a step of causing the powder feeder to drive the lower half holding tool to vibrate, so as to vibrate the heat conductive sheet, and a duration of vibrating the lower half holding tool being settable on the powder feeder.
 10. The method of manufacturing heat sink plate as claimed in claim 1, wherein the powder feeder includes a sliding mechanism provided below the lower half holding tool for moving the lower half holding tool into and out of the powder feeder in the process of manufacturing the heat sink plate. 